In the field of telecommunication, usually, we have multiple devices communicating through a network to exchange information in order to achieve a desired result or function. The security and accuracy of the information transmitted is of great importance and it must be maintained at optimal levels all through the period of transmission until reception. Transmitted information is secured through the process of encryption. At the receiving end, the received information is decrypted and the process of transmission is complete. Due to ambiguity of encryption however, in the existing telecommunication systems like HSPA, HSPA+ and UMTS, there is a failure in decryption for prolonged periods of no reception of data frames of information at the receiver.
A decryption key is used at the receiver end which is a combination of the hyper frame number (HFN) and a sequence number termed the RLC-SN (radio link control-sequence number). The RLC-SN is seven bits long and wraps around after the transmission of every 128 protocol data units (PDUs). At the instant of RLC-SN wraparound, the HFN is to increment. Due to ambiguity of encryption, a scenario arises wherein after prolonged periods of no reception of information, the RLC-SN wraparound takes place and the HFN is not incremented. The HFN value used is thus erroneous and the deciphering operation will fail. The user at the receiving end perceives the received information as garbled noise. A method and system is thus needed to remove the aforementioned inefficiencies.